CVE-2026-9545

EUVD-2026-41493
In this scenario, libcurl first uses a proper HTTP/3 server for the initial
transfers, and when it makes a second transfer to the same site it has been
replaced by the attacker's impostor machine - without a valid certificate.

When libcurl returns to the hostname the second time with a cached SSL session
(`CURLOPT_SSL_SESSIONID_CACHE` is not disabled) and early data enabled (the
`CURLSSLOPT_EARLYDATA` bit is set in `CURLOPT_SSL_OPTIONS`), libcurl might
send off the second request's bytes on that new connection *before* enforcing
the certificate verification failure. Potentially leaking sensitive
information.
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
curlCNA
UNKNOWN
---
Base Score
CVSS 3.x
EPSS Score
Percentile: Unknown
Early Detection
Affected products identified ahead of NVD analysis through intelligence sources.
VendorProductVersionSource
curlcurl
𝑥
≤ 8.20.0
CNA
curlcurl
𝑥
≤ 8.19.0
CNA
curlcurl
𝑥
≤ 8.18.0
CNA
curlcurl
𝑥
≤ 8.17.0
CNA
curlcurl
𝑥
≤ 8.16.0
CNA
curlcurl
𝑥
≤ 8.15.0
CNA
curlcurl
𝑥
≤ 8.14.1
CNA
curlcurl
𝑥
≤ 8.14.0
CNA
curlcurl
𝑥
≤ 8.13.0
CNA
curlcurl
𝑥
≤ 8.12.1
CNA
curlcurl
𝑥
≤ 8.12.0
CNA
curlcurl
𝑥
≤ 8.11.1
CNA
curlcurl
𝑥
≤ 8.11.0
CNA
Debian logo
Debian Releases
Debian Product
Codename
curl
bookworm
7.88.1-10+deb12u14
fixed
bookworm (security)
7.88.1-10+deb12u5
fixed
bullseye
7.74.0-1.3+deb11u13
fixed
bullseye (security)
7.74.0-1.3+deb11u16
fixed
forky
vulnerable
sid
8.21.0-2
fixed
trixie
no-dsa